Namespace alternative: Sengi vs Namespace for GitHub Actions runners

What is the best Namespace alternative for GitHub Actions runners?

Sengi. Every job runs on an AMD Ryzen 9 7950X3D desktop CPU boosting past 5 GHz, on bare metal with local NVMe, in a fresh VM for every job, and 2 vCPU jobs start on a pre-booted VM in 2 seconds. Builds finish up to 1.9× faster than on GitHub’s runners, for up to 74% less per build. For the same 2 vCPU and 8 GB, a minute costs $0.003 on Sengi against $0.006 on Namespace pay as you go and $0.004 inside a Namespace plan from $100 a month. No plan, no unit minutes to convert, and the cache is included.

Last checked October 23, 2026, against Namespace's pricing page. Linux x64, USD, list prices per minute.

How do Sengi and Namespace compare?

Both keep your CI in GitHub Actions and replace the machine behind runs-on. Here is where they differ.

Namespace figures: Namespace's pricing page, checked October 23, 2026.

What does Sengi cost against Namespace?

Matched shapes, Linux x64, per minute. Namespace's pay-as-you-go column is the rate its pricing page lists for usage beyond a plan; its in-plan column is the effective rate of the minutes a plan includes.

Half Namespace's pay-as-you-go rate and 25% under its in-plan rate, at every size, with no plan to buy. The same three builds on RunsOn's open benchmark harness cost $0.069 on Sengi against $0.098 on Namespace. 3,000 minutes are included on Sengi every month. Try your own numbers in the GitHub Actions cost calculator, or see Sengi runner pricing.

Namespace vs Blacksmith vs Sengi: what does each charge?

Sengi is the lowest of the three at every size, and the smallest bill for the same builds. Sources: Namespace's and Blacksmith's pricing pages, checked October 23, 2026; build costs from RunsOn's open benchmark harness, run on Sengi October 9, 2026, against RunsOn's published results. See Sengi vs Blacksmith and the full runner comparison.

How fast is Sengi?

Against GitHub’s runner of the same size on RunsOn’s open benchmark harness at 4 vCPU, Sengi builds a production Docker image 1.9× faster at 74% less per build, and runs Rust, TypeScript and Docker builds together 1.8× faster at 72% less, with 15× the random-read disk speed. On the same 2 vCPU as GitHub’s ubuntu-latest, it delivers up to 3× the multi-core and 1.65× the single-core CPU. More in faster GitHub Actions runners.

How do I switch from Namespace to Sengi?

Change runs-on from your Namespace label or profile to the Sengi label of the same size, and merge.

jobs:
  test:
    runs-on: sengi-standard-4-ubuntu-2404   # or sengi-standard-2-ubuntu-2404, sengi-standard-8-ubuntu-2404

Cache steps keep working: actions/cache and Docker's type=gha cache are served from Sengi's own cache. Or give your coding agent one prompt and it opens the pull request for you. See how switching works. Switching back is one revert.

Frequently asked questions

What is the best Namespace alternative for GitHub Actions runners?

Sengi. Every job runs on an AMD Ryzen 9 7950X3D desktop CPU boosting past 5 GHz, on bare metal with local NVMe, in a fresh VM; 2 vCPU jobs start on a pre-booted VM in 2 seconds. For the same 2 vCPU and 8 GB, a minute costs $0.003 on Sengi against $0.006 on Namespace pay as you go and $0.004 inside a Namespace plan from $100 a month.

How does Namespace pricing work?

Namespace bills unit minutes. One unit is 1 vCPU and 2 GB of memory for a minute, and a machine counts as the larger of its vCPU count and its memory in GB divided by two, times a platform multiplier of 1 for Linux. A 2 vCPU, 8 GB Linux runner is 4 units: $0.006 a minute pay as you go, or $0.004 a minute out of a Team plan's 100,000 included unit minutes at $100 a month.

Is Sengi cheaper than Namespace?

Yes, at every matched size. Sengi charges $0.003, $0.006 and $0.012 a minute for 2 vCPU with 8 GB, 4 vCPU with 16 GB and 8 vCPU with 32 GB. Namespace lists $0.006, $0.012 and $0.024 for those shapes pay as you go, and $0.004, $0.008 and $0.016 inside a plan. On RunsOn's open benchmark harness, the same Rust, TypeScript and Docker builds at 4 vCPU cost $0.069 on Sengi against $0.098 on Namespace.

Namespace vs Blacksmith: which costs less?

Blacksmith lists $0.004, $0.008 and $0.016 a minute at 2, 4 and 8 vCPU, the same as Namespace's in-plan rate, without the plan. Namespace pay as you go is $0.006, $0.012 and $0.024. Sengi costs less than both at every size: $0.003, $0.006 and $0.012.

Does Sengi have cache volumes like Namespace?

Sengi includes the cache instead of metering it. actions/cache, the setup actions' caches and Docker layer caching through type=gha are served from Sengi's own cache with no workflow changes and no per-GB charge. Namespace meters cache volume storage at $0.0048 per GB-day and snapshots at $0.002 per GB-hour on its Developer plan.

How do I switch from Namespace to Sengi?

Change runs-on from your Namespace label or profile to sengi-standard-2-ubuntu-2404, sengi-standard-4-ubuntu-2404 or sengi-standard-8-ubuntu-2404 and merge. Your workflows stay GitHub Actions workflows, and your coding agent can open the pull request for you from the Sengi prompt.